<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript" charset="utf-8">
			
			var b=123
			var flag=true
			//字符串:
			//第一种:String()
			console.log(String(b))
			console.log(String(flag))
			//第二种:toString()
			console.log(b.toString())
			console.log(flag.toString())
			
			//布尔
			var a=['false',null,'',undefined,NaN];
			for (var i = 0; i < a.length; i++) {
				console.log(typeof Boolean(a[i]))
				}
			
		</script>
	</head>
	<body>

	</body>
</html>
